Everyone knows the frustration of washing their hands in a public restroom and the paper towel dispenser being empty. Frequently this occurs because a janitor only periodically checks the supply of paper towels within the paper towel dispenser and/or a sudden influx of bathroom users was unanticipated. If the paper towel dispenser's supply of paper towels becomes exhausted, the janitor may not be aware of the need for refilling until a later visit to the bathroom, possibly hours or even days later.